On Sun, May 02, 2021 at 12:17:51PM +0200, Christophe JAILLET wrote: > Le 02/05/2021 à 00:50, Khaled ROMDHANI a écrit : > > Fix the warning: variable 'zone' is used > > uninitialized whenever '?:' condition is true. > > > > Fix that by preventing the code to reach > > the last assertion. If the variable 'mirror' > > is invalid, the assertion fails and we return > > immediately. > > > > Reported-by: kernel test robot <lkp@xxxxxxxxx> > > Signed-off-by: Khaled ROMDHANI <khaledromdhani216@xxxxxxxxx> > > --- > > fs/btrfs/zoned.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c > > index 8250ab3f0868..23da9d8dc184 100644 > > --- a/fs/btrfs/zoned.c > > +++ b/fs/btrfs/zoned.c > > @@ -145,7 +145,7 @@ static inline u32 sb_zone_number(int shift, int mirror) > > case 2: zone = 1ULL << (BTRFS_SB_LOG_SECOND_SHIFT - shift); break; > > default: > > ASSERT((u32)mirror < 3); > > - break; > > + return 0; > > } > > ASSERT(zone <= U32_MAX); > > > > base-commit: b5c294aac8a6164ddf38bfbdd1776091b4a1eeba > > > Hi, > > just a few comments. > > If I understand correctly, what you try to do is to silence a compiler > warning if no case branch is taken. > > First, all your proposals are based on the previous one. > I find it hard to follow because we don't easily see what are the > differences since the beginning. > > The "base-commit" at the bottom of your mail, is related to your own local > tree, I guess. It can't be used by any-one. > > My understanding it that a patch, should it be v2, v3..., must apply to the > current tree. (In my case, it is the latest linux-next) > This is not the case here and you have to apply each step to see the final > result. > > Should this version be fine, a maintainer wouldn't be able to apply it > as-is. > > You also try to take into account previous comments to check for incorrect > negative values for minor and catch (the can't happen today) cases, should > BTRFS_SUPER_MIRROR_MAX change and this function remain the same. > > So, why hard-coding '3'? > The reason of magic numbers are hard to remember. You should avoid them or > add a comment about it. > > My own personal variation would be something like the code below (untested). > > Hope this helps. > > CJ > > > diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c > index 70b23a0d03b1..75fe5f001d8b 100644 > --- a/fs/btrfs/zoned.c > +++ b/fs/btrfs/zoned.c > @@ -138,11 +138,14 @@ static inline u32 sb_zone_number(int shift, int > mirror) > { > u64 zone; > > - ASSERT(mirror < BTRFS_SUPER_MIRROR_MAX); > + ASSERT(mirror >= 0 && mirror < BTRFS_SUPER_MIRROR_MAX); > switch (mirror) { > case 0: zone = 0; break; > case 1: zone = 1ULL << (BTRFS_SB_LOG_FIRST_SHIFT - shift); break; > case 2: zone = 1ULL << (BTRFS_SB_LOG_SECOND_SHIFT - shift); break; > + default: > + ASSERT(! "mirror < BTRFS_SUPER_MIRROR_MAX but not handled above."); > + return 0; > } > > ASSERT(zone <= U32_MAX); > Thank you for all of your comments. Yes, of course, they will help me. I will try to handle that more properly. Thanks again.